In recent years, a demand for development of food or drink with a new aroma or taste is becoming increasingly stronger along with the diversification of the consumer's tastes. This is because it is possible to make a product different from others and to have superiority by imparting new aroma and taste to food and drink. However, in a case where an existing raw material is processed according to a conventional method, an obtainable flavor is nothing more than an extension of a conventional flavor even when the conditions of processing are changed. Thus, it is generally difficult to create an absolutely new flavor. Therefore, in order to impart an absolutely new flavor to food or drink, it is necessary to develop (1) a method for processing an existing raw material in a new manner, (2) a method for processing a new raw material in a conventional manner, and (3) a method for processing a new raw material in a new manner.
The decision of which methods among the above mentioned methods to use is made depending on the properties of food or drink to be manufactured. For example, since raw materials of beer are limited to malt, hops, rice, etc. in the Liquor Tax Law, the development of new raw materials for beer has limitations. Therefore, it is necessary to develop a technique for imparting a new flavor to beer by processing an existing raw material in a new manner.
On the other hand, in a case of happoushu or other drinks like beer (“happoushu” in the below descriptions), so long as it is manufactured using malt as a raw material and is effervescent, raw materials other than malt and manufacturing methods are not limited. Therefore, it is relatively easy to increase the variety of flavors of happoushu by the use of new raw materials. For example, in order to impart a new flavor to happoushu such as a beer-like beverage, an absolutely new raw material obtained by adding an additional other material to an existing raw material such as malt can be used (see, for example, Claim 1 etc. of Japanese Patent Laid-open No. Hei 9-37756). However, it is not easy to obtain an absolutely new flavor as long as an existing raw material such as malt used now. Therefore, it is also necessary to develop a technique for imparting an absolutely new flavor to happoushu or the like by processing an existing raw material in a new manner.
Heretofore, various methods for processing existing raw materials such as malt have been developed. For example, in a case of beer manufacture, the specialty malt such as melanoidin malt or caramel malt is used as one of raw materials in order to control the color or flavor of beer products. Such specialty malt is manufactured by roasting malt at a higher temperature than usual in a process of malt manufacture to allow caramelization or the Maillard reaction to occur. Specifically, malt is normally roasted for about 2 to 6 hours at about 80° C. to stop germination. On the other hand, melanoidin malt is manufactured by roasting malt for about 2 to 6 hours at about 100 to 130° C. in open air, and caramel malt is manufactured by roasting malt for about 2 to 6 hours at about 130 to 160° C. in open air.
However, such a specialty malt manufacturing method involves a problem that input energy is large due to high temperature roasting. From the viewpoint of reduction in the input energy, technical developments to reduce the time for roasting is desired.
Further, the specialty malt manufacturing method also involves a problem in that substances contained in malt are oxidized, because malt is roasted in an open system where oxygen is continuously supplied. The such oxides produced have adverse effects on the quality of beer or happoushu. Among such oxides, lipid peroxides and aldehydes produced due to the oxidation of lipids contained in the malt deteriorate beer or happoushu in flavor. For example, an oxidized smell is given and a bad aftertaste is left on the tongue. In addition, such lipid peroxides and aldehydes also reduce head retention and impair flavor stability. For this reason, it is desired to develop a technique for suppressing the oxidation of lipids contained in raw materials when the raw materials such as malt are processed.
Under these circumstances, various methods for minimizing the oxidation of substances in the process of manufacturing alcoholic drink using malt or the like as a raw material are being actively investigated, and some methods have already been disclosed (see Japanese Patent Laid-open No. JP-A-2000-4866, No. 2000-2701, and No. 2002-131306). Further, a technique for removing lipids from raw materials by the use of supercritical CO2 has also been developed (see Japanese Patent No. 3255962). However, a technique for suppressing the oxidation of lipids contained malt to be used as a raw material in a process of manufacturing the malt has not yet been developed.